Each galaxy lives within its own three-dimensional halo of dark matter whose gravitational field corrals the stars within it. Without the stars, the halo would still be there, albeit invisible to our eyes; but if the halo vanished, the stars would scatter into the depths of the universe – just as a Christmas tree remains a tree with or without the pretty lights. Whereas without the tree, the lights would merely be a puddle of colour on the snowy ground.
Showing visitors around the University of Auckland can be a quick lesson in our colonial history. The University is named for the city, which is named for a spectacularly unsuccessful Governor-General of India. Our oldest streets are centred on Queen Street — which is crossed by Victoria Street. The settlers took a belt and braces approach to honouring their young monarch when the city was laid out in 1841.
Imagine living in a world where walking and biking was as safe – by Commander Hadfield's measure – as flying in space.
No-one seems to dispute that the video was played, but minimising it as a conversation starter or "just one viewpoint" will not inspire confidence. If this was part of a wider programme to slip creationism into science classes, it speaks to a failure of leadership and, I believe, integrity.
If you're a teacher, what's your ambition? It's got to be better to watch your students chase their dreams than, when they come to tell the story of their success, be remembered as the person who said they couldn't do it.